informed by the absence of an indication that a constructive trust would
have an unfair or unjust effect on the defendant or third parties, matters
which equity has always taken into account. Equitable remedies are flexible;
their award is based on what is just in all the circumstances of the case.

Good conscience as a common concept unifying the various instances in
which a constructive trust may be found has the disadvantage of being very
general. But any concept capable of embracing the diverse circumstances in
which a constructive trust may be imposed must, of necessity, be general.
Particularity is found in the situations in which judges in the past have
found constructive trusts. A judge faced with a claim for a constructive trust
will have regard not merely to what might seem “fair” in a general sense, but
to other situations where courts have found a constructive trust. The goal is
but a reasoned, incremental development of the law on a case-by-case basis.

(Emphasis added)

[182] These statements, in my view, decisively refute the
appellant’s argument that a court can impose a constructive
trust now in only two categories of cases: to remedy an unjust
enrichment or a wrongful act.

[183] I acknowledge that McLachlin J. then turns, at para. 36,
to address specifically the two dominant categories of unjust
enrichment and wrongful acts as bases for imposing a constructive trust. She innovated somewhat by more firmly establishing
remedial constructive trusts as a remedy for wrongful acts, at
para. 45, which was the basis on which she decided Soulos itself.

[184] The Supreme Court plainly knew Soulos was carving out
new ground. This was acknowledged by Sopinka J., in dissent,
who criticized the majority’s decision, at para. 72, because it
“fails to refer to a single Canadian case where a constructive
trust was ordered despite the absence of unjust enrichment”.

[185] But I note that nowhere did McLachlin J. abandon as
spent the continuing development of the law of constructive
trusts: see paras. 20-25 and 34-35 of Soulos, quoted above.

(5) Concluding observations on Soulos

[186] In my view, the Supreme Court left open four routes by
which a court could impose the [at para. 17] “ancient and eclectic
institution” of a constructive trust: (1) unjust enrichment;
(2) wrongful acts or wrongful gain; (3) circumstances where its
“availability has long been recognized” (para. 21), such as “
situations where a constructive trusts have been recognized in
the past” (para. 34) or “other situations where courts have
found a constructive trust” (para 35); and (4) otherwise, where
good conscience requires it. In relation to this last point, the
Soulos court anticipated that the law of remedial constructive
trusts would continue to develop, consistent with the words of
Dickson J. in Pettkus, at p. 847-48 S.C.R.: “the judiciary is thus